PROJECT SUMMARY/ABSTRACT Pediatric overweight and obesity continue to be major public health issues. Loss of control (LOC) eating is an obesity-related phenotype that affects approximately 30% of children and adolescents with overweight/obesity and may impede successful weight control. Both pediatric overweight/obesity and LOC eating are associated with relative deficiencies in executive functioning. In particular, our recently published data suggest that youth with LOC eating and concomitant overweight/obesity have poorer working memory (WM) than their overweight/obese and non-overweight peers. These decrements may inhibit their abilities to adaptively respond to environmental and internal cues related to eating. A limitation of prior research is that it has largely focused on individual differences in neurocognitive processes, thereby failing to inform our understanding of how these processes may drive eating behavior on a moment-to-moment basis and limiting development of interventions that can be delivered in real time when individuals are most at risk for engaging in LOC eating. This R03 application proposes to use ecological momentary assessment (EMA) and validated dietary assessment (Nutritional Database System for Research; NDSR) to assess eating behavior in the context of acute WM, and assess whether fluctuations in WM are related to LOC eating or excess energy intake in children (10-17 years) with LOC eating and overweight/obesity relative to their overweight/obese and non- overweight peers. The applicant is a current K23 recipient (DK-105234) whose program of research has focused on clarifying the etiology and maintenance of LOC eating in youth with overweight/obesity. The applicant's expertise in momentary assessment of affective and neurocognitive processes underlying eating- and weight-related disorders forms the basis of the current proposal. In particular, the applicant has extensive experience utilizing EMA to understand antecedents and consequences of maladaptive eating in near real time in the natural environment. EMA is ideal for investigating eating behavior in the context of WM as it allows for prospective, momentary assessment of within- and between-person variables of interest. In the proposed study, participants will monitor their eating behavior via EMA for 14 days, and dietary recalls completed on 3 randomly selected days during this same period. They will also complete EMA tasks of numerical and spatial WM. Data on potential covariates (e.g., mood) will also be collected via EMA. These data will clarify timing and trajectory of LOC eating and dietary intake in relation to WM performance. This study, which is the first to use EMA to clarify if momentary WM performance is related to eating behavior, has clear potential to advance scientific and clinical understanding of mechanisms that promote the occurrence of maladaptive eating in youth and inform interventions to alleviate their cumulative personal and societal burden. Furthermore, this proposal provides a clear pathway to independence for the investigator, and will enable her to pursue future R01 funding to understand the impact of WM training on eating- and weight-related outcomes.